Did you put the leads on each side of the tunnel, or each end? And the electricity flowed through the ground and electrocuted the moles?
It sounds fun.
Two 6 inch probes on both sides of the hole. They came up squealing. I haven't seen the device since then.
Now days the local Catfish has summer warfare with the squirrels and their impact on fruit from pear, peach, and plum trees.
Two years ago, I nailed one with a pellet rifle, and hung him up 15' in one of the trees, to send a reminder to his friends. Part of his petrified carcass still waves in the wind.